Pump



April 7, 1959 R. COVER 2,880,679

- v PUMP Original Filed Feb. 1a, 1955 9' Sheets-Sheet 1 INVENTOR Ea (pi('0 Ver WM f ATTORNEYS April 7; 1959 R. COVER ,6

v PUMP Original Fil d Feb. 18, 1955 v 9 Sheets-Sheet 2 lNVlNTOR a 60% Cow ATTORNEYS April 1959 COVER 2,880,679

PUMP

Original Filed Feb. 18, 1955 I 9 Sheets-Sheet 3 ATTORNEYS v INVENTORApril 7,1959 R. COVER 2,880,679

PUMP I Original Filed Feb. 18, 1955 9 Sheets-Sheet 4 VF/a. 5.

INVENTOR flan p23 Co yer ATTORNEYS April'7, 1959 v R. COVER 2,880,679 IPUMP Original Filed Feb. 18 1955 9 Sheets-Sheet 5 FIG. 6'.

INVENTOR 6; vfi U0 yer ATTORNEYS R. COVER April 7, 1959 PUMP 9Sheets-Sheet 6 INVENTOR ATTORNEYS R. COVER April 7, 1959 PUMP 9Sheets-Sheet 8 Original Filed Feb. 18, 1955 INVENTOR Rd 230% ('0 weATTOR NEW United States Patent PUMP Ralph Cover, Westminster, Md.

1 Claim. (Cl. 103-126) This application is a division of my applicationSerial .No. 489,236, filed February 18, 1955. The present inventionrelates primarily, though not exclusively, to an improved apparatus forreducing, grinding, milling, and mixing vegetable materials in the freshstate and, more particularly, to the making of the fluid constituent ofcream style corn. The treatment of such materials presents special andunusual problems, not encountered in the milling, grinding, or reducingof other materials, and procedures and equipment found satisfactory inother fields are entirely unsatisfactory and produce inferior resultswhen employed in the preparation of a creamy liquid from fresh cornkernels.

The apparatus shown in the present application is particularly adaptedfor use in producing the finely divided corn grain constituent or creamof the product described in and adapted to be employed in the processcovered by United States Patents 2,484,375 and 2,484,376, Ralph Cover,October 11, 1949. The process described in said patents and the productsresulting therefrom have created what may be termed a revolution in thecorn canning industry, and reasonably satisfactory machines have beendeveloped for producing the cream constituent of the product, but thosemachines left much to be desired from the commercial standpoint, withrespect to their rate of production of the cream corn constituent, theirsanitary characteristics, including ease of cleaning and sterilization,and the uniformity and excellence of the product.

An object of the invention is to provide a positive force feed for themill, so that the material is tightly compacted before being treated, toexclude air and to effect the treatment substantially in the absence ofoxygen.

Another object of the invention is to provide means for varying thepressure exerted on the material prior to its passage through themilling zone and to observe this pressure constantly, so that theoptimum pressure at all stages may be employed at all times.

Still another object of the present invention is the provision of a pumpparticularly for use in delivering material to a mill or the like whichis simple in construction, efficient in operation and economical tomanufacture and maintain.

Other and further objects and advantages of the invention, such asimproved sanitary features, ease of assembly and disassembly, and thelike, will be apparent from a consideration of the preferred embodimentof the invention, shown for purposes of illustration in the accompanyingdrawings and described below.

In the drawings,

Figure 1 is a front perspective view of the apparatus;

Figure 2 is a rear perspective, looking in substantially the oppositedirection from Figure 1;

Figure 3 is a fragmentary rear elevation with certain parts broken awayfor the sake of clarity;

Figure 4 is a fragmentary plan view on an enlarged scale of a preferredform of hinged connection between the screw feeder and the mill proper;

2,880,679 Patented Apr. 7, 1959 Figure 5 is an enlarged vertical sectiontaken substanv tially on line 5--5 of Figure 3;

Figure 6 is a similar horizontal section, on line 6-6 of Figure 3;

Figure 7 is an elevational view of a pair of connected back platecastings, to which the milling heads are adapted to be secured;

Figure 8 is a vertical longitudinal sectional view of the left handmilling head shown in perspective in Figure 1;

Figure 9 is an exploded, perspective view of the left hand back platecasting and the component parts of the infeed pump and milling head;

Figure 10 is a face view of one of the stator plates of the millingheads;

Figure 11 is a similar view of one of the rotor plates;

Figure 12 is a view showing the rotor superimposed on the stator; s

Figure 13 is a greatly enlarged fragmentary section on line 13-13 ofFigure 12; and

Figure 14 is a similar section on line 14-14 of-Figure 11.

General organization Referring to Figures 1 and 2, the machine of thepresent invention comprises, in general, a heavy unitary base casting10, including a top 11, a front wall 12, a rear wall 13, a right handside wall 14 and a left hand side wall 15 Heavy doors 16 and 1-7 areadapted to close enlarged openings in the front and right hand sidewalls, respectively, while a smaller door 18 is hingedly mountedadjacent a smaller opening in the left hand side Wall.

Supported upon the rear portion of the top 11 is an upstanding gearcasing 19, having its 'open upper end closed by a closure plate 20. Nearthe front of the top 11, there is a screw conveyor power transmissionand supporting housing 21, including a laterally projecting portion 22and an upwardly projecting portion 23. The latter carries the housing 24of an infeed screw conveyor, adapted to deliver material to the millproper.

Mounted in the front face of the gear casing 19 are a pair of back platecastings 25 and 26, to which the two milling heads, representedgenerally at 27 and 28 are secured. The outlet for the milled materialis shown at 29 and is adapted to be connected to a discharge pipe or thelike, to convey the material to the next point of treatment in theplant.

Machine drive A pair of vertically disposed angle irons, secured to theleft hand wall of the base 10, one of which is shown at 30 in Figure l,pivotally support at 31, a platform 32 upon which an electric motor 33is supported, the other edge of the platform being adjustably connectedby a plurality of bolts 34 to a flange or angle element, not shown,carried by the lower portion of the base 10, below the large opening inside wall 14. Hence, the platform may be raised and lowered about thepivots 31, to tension the belts hereinafter referred to.

The motor shaft 35 (Figures 2 and 3) carries a multiple V-belt pulley36, about which a set of six V-belts 37 are trained. An upper pulley 38,fast on a shaft 39, journalled in the gear case 19 accommodates theV-belts and is driven thereby. As shown in Figure 5, the shaft issupported by roller bearings 40 and 41 in accordance with good,conventional engineering practice. A spur gear 42, fast on the shaft 39drives an upper, intermediate spur gear 43 and a lower gear 44, fast ona shaft 45 journalled in the gear casing and extending forwardly to thescrew conveyor drive housing 21.

The upper intermediate gear 43 is journalled upon'a stationary stubshaft carried by the back wall "of the gear casing 19 as shown inFigures and 6. Referring to the latter figure, this upper intermediategear 43 is in mesh with two spur gears 47 and 48, non-rotatably secured,respectively, on milling head drive shafts 49 and 50. The shaft 49 isjournalled by roller bearing assemblies 51 and 52, in accordance withgood conventional engineering practice, in the front and rear walls ofthe gear casing 19, while the shaft 50 is similarly mounted in bearingassemblies 53 and 54.

The milling head drive shafts 49 and 50 have keyed thereto second spurgears 55 and 55 in mesh with gears fast on upper gear pump shafts 57,one of which spur gears is shown at 56 in Figures 8 and 9.

Referring to Figures 1, 2 and 3, the shaft 45 which is the drivingelement for the transmission leading to the infeed screw in the conveyorhousing 24, as stated above, is journalled at its forward end in thetransmission housing 21. This end of the shaft carries a sprocketindicated diagrammatically at 60 in Figure 3, about which a drivingchain 61 is trained. The lower run of this chain travels about a loweridler sprocket 62 and then extends upwardly where it is trained about asprocket 63 on the shaft of a conventional worm or screw conveyordisposed within the feeder housing 24 but not shown in detail in theaccompanying drawings, since the construction is conventional and may bepurchased on the market. The upper run of the chain 62 passes under anadjustably mounted idler sprocket 64, to which access may be had throughan appropriate opening, by removing a closure plate 65 (Figure 1). Thus,the worm or screw associated with the feeder is rotated by the electricmotor 33, through the gears referred to above, the shaft 45 and thechain 61, to deliver corn or other material deposited in the hopper 24ato and through the delivery spout 68.

Delivery of material to machine The delivery spout 68 is of specialconstruction and is arranged and mounted to facilitate readydisassembly, cleaning and reassembling. As best shown in Figure 4, theback face of the gear housing 19 carries a bracket 69 having a pair ofrearwardly projecting apertured lugs 70 thereon, carrying a pin 71, towhich a link 72 is pivoted. The other end of the link is similarlyconnected by a pin 73 to the bifurcated end 74 of an arm 75 having atits other end an annular portion 76, provided with an annular recess inwhich an O-ring 77 is positioned in encircling relation to the centralopening 78.

The spout 68 comprises a casting having a laterally turned lower rearend 80 secured to and carried by the annular portion 76 of thesupporting arm or bracket 75 and having its throat in registry with theopening 78. A plate 81 covering an opening in the throat 80 carries anelectro-magnet 81 adapted to attract and catch tramp metal which mightotherwise enter the machine and damage the pump elements or the millingdiscs. The upper, enlarged, outwardly flaring portion of the throat 68is outwardly flanged and is embraced by a split collar comprising anupper half 82 and a lower half 83, adapted to engage in clampingrelation the last mentioned flange and a similar flange on the dischargeend of the housing 24 of the screw conveyor, to draw the spout and thehousing tightly into engagement and to hold the parts in that relation.The split ring is maintained in closed position by a pivoted bolt andwing nut assembly of known construction, indicated generally at 84 inFigure 3.

The left hand end face of the left hand back plate casting 25 (Figures 4and 7) is provided with an outwardly projecting annular boss 85 having aplain outer surface against which the O-ring 77 is adapted to seat, inhermetically sealed relation, when the spout 68 is firmly clamped uponthe housing 24 of the infeed conveyor as described above. When the splitring assembly is opened, the spout and the arm or bracket 75 may beswung rearwardly for inspection and cleaning.

Force feed to mills The back plate castings 25 and 26 are mounted in atransversely extending recess formed in the front face of the upwardlyprojecting gear housing 19. The annular boss 85, as best shown in Figure7, surrounds an inlet passage 91 formed in the casting 25 and having itsother end opening through the front face as indicated at 93. The castingis cored at 94 and 95 to provide intercommunicating water jacket spacesadjacent the upper half thereof, and at 96 and 97 to provide similarpassages of spaces at the lower portion thereof. Additionally, thecasting is provided with upper and lower bores 98 and 99, through whichfree end portions of the shafts 57 and 49 overhung from the castingextend, the bores being formed in inwardly recessed portions 100, 101,communicating with a downwardly extending groove 102 for purposeshereinafter explained. A plurality of tapped holes 103 are formed in thecasting around the circumference of the raised, forwardly projecting,circular central portion 25' thereof, to receive a plurality offorwardly projecting rods 104 (Figures 8 and 9). Another circularopening 105 is formed in the face of the back plate casting, to receivea pressure gauge diaphragm or bellows, to measure the pressure of thematerial entering the mill, as hereinafter explained. Finally, the backplate casing 25 is provided with an opening 106, leading to a dischargepassage 107 terminating in an opening 108 in the right hand side face ofthe back plate casting. This side face is also provided with openings109 and 110 communicating with the water jacket spaces 95 and 96,respectively.

The right hand back plate casting 26 is generally similar to the lefthand one and serves as the support for the right hand milling head 28.Its left hand vertical side face includes an opening 112 in registrywith the opening 108 in the right hand side face of casting 25, andadditional water circulating openings 113, 114 registering with theopenings 109, 110, respectively, so that Water may circulate freelythrough the water jacket spaces 94, 95, 96', and 97', correspondinggenerally with jacket spaces 94-97 in the first back plate.

The opening 112, registering with the discharge opening 108, leads to aninlet passage 120, communicating through the face of the back platecasting 26 in an opening 121, generally similar to the opening 93 in theother back plate casting.

Additionally, the casting 26 is provided with upper and lower bores 98and 99', through which an upper gear pump shaft 57 and the lower shaft50 extend, the bores being formed in inwardly recessed portions 100',101', communicating with a downwardly extending groove 102' for purposeshereinafter explained. Tapped holes 103' are provided for the samepurpose as holes 103 in the back plate casting 25 and an opening 105 isprovided, to receive a pressured gauge diaphragm or bellows, to measurethe pressure of the material at this point in its passage through theapparatus. A discharge opening 106' is positioned in the same relativelocation as the opening 106, and communicates with a discharge passage107', terminating in an opening 108 in the right hand side face of thecasting.

In addition, the right hand side face of the casting 26 has a pair oftapped openings 109' and 110', to which cooling water conduits may beconnected for the introduction, circulation and discharge of fluidthrough the water jacket spaces or cored-out areas in the back plates.

The two milling heads 27 and 28 are substantially identical inconstruction and are both force fed by positive displacement gear pumps,the arrangement being such that material is delivered from the screwconveyor through the opening 93 in back plate 25 to the first gear pumpand from the latter through the milling discs in the first milling head27. From this head the material is delivered through opening 106,passage 107 and discharge opening 108 of back plate 25 to the inletopening 112, inlet passage 120 and opening 121 of back plate casting 26,into the inlet of the second gear pump. The latter delivers the materialto the milling discs of the second head, which perform the finalreducing operation and return the same through opening 106', passage107' to the final discharge opening 108'. Thus, the material isforcefully fed through the milling heads in series.

Since the gear pumps constituting the force feeding means are identical,a description of one will sufiice. Referring to Figures 8 and 9, showingthe left hand pump and milling head, it will be noted that a backsealing plate 125 supported on rods 104 is disposed in face-tofacecontact with the forwardly projecting, raised portion 25' of the backplate 25. The plate has a pair of openings 126 and 127 through which theshafts 49 and 57 extend. Packing glands 126 (Figure 8) and 127' aredisposed in sealing relation to the shafts, within the openings. Alsomounted upon the rods 104 is a pump chamber back plate 128 having a pairof openings 129 and 130 through which the shafts 57 and 49 project. Therear edges of these openings are somewhat countersunk to receiveforwardly projecting faces of the packing glands 126' and 127'.

Next in the series of plates supported upon rods 104 is the pump housingplate 131. This plate or casting is shaped to provide two intersectingcylindrical chambers 132 and 133, having their axes coinciding with thecenters of openings 126 and 129 and 127 and 130 of the plates 125 and128, and also aligned with the axes of shafts 57 and 49. Disposed withinthe upper chamber 132 and keyed upon the end of shaft 57 is a gear 134,having the teeth 134' thereof in mesh with similar teeth 135 of a gear135, fast on the end of the lower shaft 49. Although the gears are inmesh with each other, in the sense that the teeth on one gear arereceived in the spaces between the teeth of the other gear, they are notin driving relation, as the driving is effected through gears 55 and 56,fast on the shafts 49 and 57. The advantages of this arrangement areexplained below.

Referring to Figure 9, registering with the inlet opening 93 in the backplate casting 26 are pump inlet openings 136 and 137 in plates 125 and128 respectively. These openings register with a pump inlet chamber 138in the pump housing 131. Formed in the gear pump housing plate 131 is apump discharge chamber 139 which communicates forwardly with a pumpdelivery opening 140, in a pump chamber front plate 141, mounted on rods104 and constituting the front Wall of the pump chambers 132 and 133.The front surface of this plate 141 has a recess 142 therein,constituting the discharge passage leading downwardly from opening 140to the central openings in the milling discs described below.

As pointed out above, the gears 134 and 135 of the positive displacementgear pump are so adjusted that the teeth thereof are not in drivingrelation to each other but are out of contact by a few thousandths of aninch. This adjustment is accomplished through the gear 56 on shaft 57,which is mounted thereon for circumferential adjustment. It is thedriven gear of the pair, consisting of gears 55 and 56. As shown inFigures and 8, it has a rearwardly extending sleeve portion 56aterminating rearwardly in an enlarged relatively heavy flange 56b, bothof which are split, as indicated at 56c on diametrically opposite sides.Headed screws 56d interconnect the two semi-cylindrical bodiesconstituting the flange 56b so that the split extension of the gear maybe tightly clamped upon the shaft in any desired position of angularadjustment, for instance, to maintain the pump gears out of contact witheach other, while the gears 55 and 56 are in driving relation.

It has been found that gear pumps, working in cylinders with closetolerances and particularly when associated with shafts supported inbearings spaced from the pumping elements, tend to tip or cant slightlyon their axes .with the result that the corners of the teeth tend to digor cut into the end walls ofthe cylinders, resulting in a sloppy fit,by-passing of the material and an inefficient pumping action. Thisdifficulty in accordance with the present invention, has been overcomeby beveling or slightly relieving the end faces of the teeth at the tipsthereof. This relief may be in the range of a few thousandths of an inchand is shown greatly exaggerated in Figure 8 at and 134".

The gear pump develops substantial pressure but in the normal operationand with proper seals, no substantial leakage is to be anticipated.However, if the material being pumped should be forced inwardly andrearwardly along the shafts 49 and 57, and past the seals 126' and 127,it would be highly objectionable, if the material continued to flowalong these shafts into the gear housing, shaft bearings and the like.This possibility is prevented in accordance with the present invention,by the recesses 100 and 101 and the channel 102 formed in the face ofthe back plate casting 25 similar mating recesses and channels formed inthe rear face of the back sealing plate 125. Any material forcedrearwardly along the shafts 57 and 49 is received in these recesses andis permitted to drain from the bottom of channel.

The disc mills A first stator milling disc 143, has a plane rear facedisposed in registry with the outer face of plate 141. It is providedwith an enlarged cylindrical opening 144 arranged coaxially with respectto the lower shaft 49. This opening is in communication with thedischarge passage 142 in the face of plate 141. On the outer face ofplate 143, surrounding the opening 144 are aplurality of milling grooves145, described in detail below and a plurality of smaller ribs andgrooves or serrations as indicated generally at 146.

Also mounted on the rods 104 and disposed outwardly of the stator plate143 is a casting constituting a mill housing plate or block 147 having acylindrical interior 148. The latter opens laterally with an enlargement149, acting as a material discharge passage as hereinafter explained.The milling chamber 148 is closed at its outer end by a sealing plate150 also mounted on rods 104. Finally there is an outer cover plate 151carried by rods 104, with certain adjuncts and features described below.

The cylindrical side wall of the chamber 148 is also provided with upperand lower key ways 152, 153, respectively, to retain the floating statorplates in position, as hereinafter explained.

Splined upon the lower shaft 49 for rotation therewith, and withcapability for axial adjustment, are a pair of spaced rotor millingdiscs 154 and 155. Interposed between them is a floating stator plate156 and, at the outer end of rotor is a floating end stator disc 157.

Disc mill rotors 155 and 154 are substantially identical and include(Figure 11) a plurality of openings 160 in their central areas, formedbetween inwardly projecting legs 161, which terminate in ends 162,adapted to be received in ways or splines 163 in shaft 49. The centralportions of the rotors, including the surfaces of the legs 161 arerecessed inwardly a substantial distance from the milling faces 164 andare connected thereto by inclined or conical wall sections 165. Thepitch of the incline 165 between surfaces 161 and 164 is relativelysteep. A plurality of milling grooves 167, referred to above inconnection with stator 143 as grooves 145, are formed in the othermilling discs. Also the milling faces of the rotors 154 and 155 areprovided with ribs and grooves or serrations 168, similar to those shownat 146 on the face of stator 143. These serrations preferably take theform of narrow, shallow, closely spaced grooves cut on intersectingcircles having their centers on the circumference of a circle 169concentric with the circular outer edge of the rotors.

The bottoms of the milling grooves 167 extend at their inner ends fromthe plane of the inner edge of the inclined or conical sufrace 165,which coincide with the plane of the faces of the legs 161 outwardly onan arc of long radius to the plane of the face 164. They are disposed onstraight lines arranged in angular relation to radii of the discs andare pitched outwardly and forwardly relative to the direction ofrotation, on both faces of the rotor discs 154 and 155.

The stator disc 156 (Figure 10) is similarly formed, with an inclinedbeveled or conical section 17%} on both faces between the millingsurfaces 171 and the central opening 172. The milling faces are providedwith circular grooves 168' identically arranged to grooves 163 on therotor faces. However, the outwardly extending shearing or millinggrooves 173 are pitched in the opposite direction, as compared to theshearing grooves 167 formed in the faces of the rotors.

The end stator disc 157 has its inner milling face configuratedidentically to the corresponding faces of stators 143' and 156. However,the central recess 174 does not extend all the way through the plate.Both stator discs 157 and 156 are provided with projections or keys 157'and 156, adapted to be received in the grooves 152 and 153 to preventrotation of the discs. Also their peripheries are provided with flats156a and 157a to establish intercommunication between the annularchambers which receive the ground material, between the inner surface ofthe chamber 148 and the peripheries of the rotors 154 and 155, whichchambers, of course, deliver material into the lateral enlargement orpassage 149.

An important detail of construction of the milling discs is the relativedisposition of the milling or shearing grooves 167 on the rotor discsand the grooves 173 on the stator discs and their cross-sectionalshapes. Grooves 145 on stator 143 are identical to grooves 173. Aspointed out above, the shearing grooves are oppositely pitched on therotors and stators with respect to each other. Hence, material forcedinto the grooves from the openings adjacent the central portions issubjected to a shearing action by the edges of the grooves as they moveover each other during rotation of the rotors. It will be understoodthat the pitch of the grooves on both faces of both rotors is the sameand that the pitch of the grooves on all surfaces of the stators is thesame but is opposite to that of the rotor grooves. Hence, the shearingaction is effective between all relatively moving surfaces. Consideringthe walls of each groove as the active milling agent, it is apparentthat, if the rotor in Figure 11 rotates in the counterclockwisedirection, the edges 167' Will be the active shearing edges and willcooperate, in the milling operation with edges 173 of the stator 156shown in Figure 10, only on the opposite face thereof. The oppositeedges of the grooves will perform substantially no shearing action. Animportant feature of the invention is that these non-shearing edges arerelieved, inclined or cut back, as indicated at 167" and 173".

The rotor 154 in Figures 11 and 12 is adapted to rotate in thecounterclockwise direction as indicated by the arrows. Figure 14 is afragmentary view showing the relationship between one milling groove ona rotor and a cooperating groove on the stator. The rotor 154 moves inthe direction of the arrow. Thus, the forwardly facing edge 167' of eachgroove, considered from the point of view of the direction of rotation,is abrupt, square to the disc surface and sharp, while the rearwardlyfacing edge 167" of each groove is inclined or relieved, making anobtuse angle to the disc surface. The grooves in the stator 156 areoppositely formed, with the edges 173 facing rearwardly toward theoncoming rotor being sharp and square to the stator surface and theedges 173" facing forwardly being relieved and disposed at an obtuseangle withrespect to the surface. The advantages and result-ingfunctions from this specific construction will be described below.

Referring again to Figures 8 and 9, the outer cover plate 151, carriedby rods 104, has a forwardly projecting hollow, externally theaded boss175 projecting therefrom. Disposed within the boss is a cylindrical plug176 having an outwardly projecting ffange 177 at its inner end, bearingagainst the outer face of the end stator disc 157. The outer end of theplug 176 is recessed, to receive the inner race of a thrust bearingassembly indicated generally at 178. A pressure adjusting cap 179 isthreaded uponthe boss of 175 with its inner face bearing against thethrust bearing assembly 178. A plurality of outwardly projecting handles18! are formed on the cap, so that it may be rotated, to apply more orless pressure upon the end stator disc 157 and to control the spacingbetween the several milling discs. A packing seal 131 is providedbetween the plates 150 and 151, and the plug 176.

It will be understood, as mentioned above, that the right hand millinghead is preferably substantially identical to the left hand one, justdescribed.

Cooling system As mentioned at the outset of this specification, animportant object of the invention is to prevent overheating of thematerial being treated and to provide positive cooling means for thematerial and at least certain of the conduits through which the materialpasses. In most cases, it has been found satisfactory simply topositively cool, by the circulation of a cooling liquid, the back platecastings 25 and 26. By maintaining these large heavy members in a cooledstate, heat from the active, friction producing parts, such as thedriving gears, the elements of the gear pumps and the milling discs, isreadily absorbed by conduction through the metal plates, rods, shaftsand the like. The material being treated passes through these backplates three times during its treatment, once when being fed to theapparatus, again when being delivered from the first milling head to thesecond, and again when being discharged. These three passes throughwater cooled conduits contribute very substantially in preventingoverheating.

If desired, cooling water may be circulated through passages formed inthe plates 125, 128, 131, 141, 143, 147 and 150, through appropriateopenings and channels, described below, but in actual practice, whenworking with such material as fresh, ripe, sweet corn kernels, suchcirculation has been found to be unnecessary and the trouble ofproviding adequate seals between the various openings, grooves andpassages has been found to outweigh the theoretical advantage whichpositive cooling provides. However, in special cases where othermaterials are being handled and where positive cooling is desirable, thefeatures now to be described may be employed, together withappropriately shaped and apertured gasket sheets interposed between thesuccessive plates, housings, etc. to solve the sealing problem. Moreover, in any case, the passages, holes, bores and the like, describedbelow, are provided, since they are advantageous in reducing the weightof the parts.

The back plate casting 26 may be provided with an opening 200communicating with the water jacket space therebehind. As best shown inFigure 9, opening 200 registers with a hole 201 in plate 125. Thisopening is in communication with groove 202 on the outer face of theplate, which registers with an opening 203 in plate 128. The latterregisters, similarly, with a bore or hole 204 in the pump housing plate131. This bore in turn is in registry with a passage 205' in the plate141 and the latter is in alignment with a bore 206 in the first statordisc plate 143. Hole 206 registers with a laterally enlarged waterjacket space 207 in the mill housing 147. The outer end of this spaceregisters with an opening 208 in the milling chamber outer end sealingplate and the latter communicates through a groove in the outer face ofthe latter plate with an opening 209 in said plate. This opening leadsthe water back through another water jacket space 210 in the millhousing 147. The latter registers with an opening 211, which may extendall the way through the plate 143 or simply be in the form of a recess,since the fluid flows therefrom through a groove 212 in the outer faceof stator plate 143 to another recess or opening 213 in the same plate.This opening is in registry with still another jacket passage 214 in themill housing 147. The fluid is again transferred by openings 215, groove216 and passage 217 in end sealing plate 150, from which point it flowsrearwardly again through the water jacket passage 218 in the millhousing 147. From the inner end of this passage, the fluid flows backthrough plates 143, 141, 131, 128 and 125, by way of openings 219, 220,221, 222, 223 therein, respectively. The opening 223 in the latter plateis at one end of a recess 224 which leads downwardly to another opening225 in the same plate. The latter delivers the fluid for forward flowthrough passages 226, 227, 228, 229, 230, and 231 in the entire seriesof plates and housings. From the opening 231 in end sealing plate 150,the fluid flows through a groove in the outer face thereof to an opening232, from which point it flows rearwardly again through a passage 233 inmill housing, and a hole 234 in plate 143 to an opening 235 in the pumpcylinder front plate 141. The opening 235 is in communication through achannel 236 with another opening 237 in plate 141.

From this opening 237 in plate 141, the cooling liquid is free tocirculate by convection currents, or the like, through relatively largeopenings 238, 239 and 240 in plates 131, 128, and 125. Also, fromopening 237 in plate 141, it flows on an independent path to the Waterdischarge opening in the back plate casting, along a circuitous route,now to be described. The flow is forwardly through opening 238' in thefirst stator plate 143, next through passage 239' in the mill housing147 and then through opening 240' in the front stator plate 150. Thelatter has a transversely extending groove 241' in its outer face,leading to an opening 242', through which the water flows rearwardlyagain, through passages 243 in the mill housing 147 and through anopening 244 in the back stator plate 143. The latter opening is inregistry with an opening 245' in plate 141, from which the water maycirculate by convection into an opening 245" in the pump housing 131.However, the principal flow from opening 245' is through a transversegroove 246' in the face of plate 141 to an opening 247' therethrough.From this opening, the liquid flows rearwardly again through a passage248 in the pump housing 131 and thence through an opening 249 in plate128 to a groove 250 in the face of the back sealing plate 125. Thelatter groove communicates with an enlarged opening 251' having aportion in registry with the discharge opening 252' in the back platecasting 25.

When this circulating system is employed it is desirable to have theupper water jacket spaces 94 and 95 out of communication with the lowerspaces 97 and 96, so that the water delivered to the upper spaces underpressure is forced to flow through the milling head and pump housingsalong the circuitous route described above, back to the lower chamberfor discharge.

Discharge of milled material into the lateral enlargement 149 in themill housing 147.

The front end of this passage 149 is closed by the outer end sealingplate 150. The inner end, however, communicates with an opening 181 inthe first stator milling disc 143 and the latter is in alignment anddelivers to Openings in plates 141, 131, 128, 125, indicated, respec- 10tively, at 182, 183, 184 and 185. The latter opening registers with theopening 106 in the back plate casting 25 which, as explained above,communicates through conduit 107 with the right hand back plate casting26.

Pressune control As shown in Figure l, the front face of the upstandinggear housing 19 carries a pair of pressure gauges 300 and 301, tomeasure the pressure being exerted on the material as it is forcedbetween the milling discs. As pointed out above, the back plate castings25 and 26 are provided with openings and 105 adapted to receiveconventional pressure responsive bellows operatively connected to thesegauges in any appropriate manner, as by flexible conduits 300' and 301.It should be noted that the back sealing plate (Figure 9) is providedwith an opening 302, registering with the opening 105 and that the pumphousing back plate 128 is provided with a registering opening 303. Theseopenings are all in direct alignment and communication with thedischarge chamber 139 of the gear pump. It will be remembered that thematerial flows from this chamber (forwardly to the central openings inthe milling rotors and stators. Hence, by gauging the pressure existingin this chamber, the pressure exerted on the material being forcedthrough the milling surfaces is determined. A small quantity of thematerial, of course, fills the openings 303, 302, and 105 and transmitspressure to the pressure responsive bellows. Thus the gauges 300 and 301register the pressure in the milling chamber.

Operation Although the mill of the present invention is adapted tooperate upon a wide variety of different materials, it has been designedprimarily, as indicated above, for reducing fresh corn kernels to afluid state, to form the creamy constituent of cream style canned corn.Hence, the operation of the apparatus will be described in connectionwith the treatment of such material.

Freshly cut kernels from green sweet corn are fed by any appropriatemeans into the hopper 24a of the screw conveyor disposed within thehousing 24, from which they are delivered by the spout 68 to the inlet91 of the left hand back plate 25. The screw conveyor serves to compactand somewhat compress the corn kernels, and to exclude substantially allof the air in the spaces between the kernels. Hence, they are fed as acompact mass of particles through the opening 93 in the back plate andthe registering openings in the next two plates to the gear pump inletchamber 138. The gears rotate in the direction of the arrows in Figure 9so that the space between each pair of teeth in each gear receives cornfed thereto under pressure and carries the same around in the pumpchamber 132 and 133 to the discharge chamber 139. Here, the teeth of onegear enter into the spaces between the teeth of the other gear and viceversa, thereby forcing the corn out of those spaces and into thedischarge chamber 39 by a known positive displacement action. Under theforce of the gear pump, the corn flows forwardly through opening in thepump front plate 141 and laterally through recess 142, the lower end ofwhich is concentric to the lower shaft 49 and the milling discs mountedon and surrounding the same. It will be noted that the first stator disc143 has an enlarged central opening 144 to receive the corn. The rotordisc 154 similarly has four openings to receive corn by longitudinalflow from the opening 144. The first floating stator plate 156 has acentral opening 172 corresponding to the opening 144 in plate 143, andthis opening 172 receives material from the openings 160 in the rotor.The next rotor has a similar series of four openings, through which thematerial may flow from opening 172, and the last floating stator plate157 has a central recess 174 registering therewith. Hence, all of theopenings in the milling plates are normally filled with material,forcefully delivered thereto from the discharge chamber of the gearpump. The material is forced outwardly into the grooves 167 and 173 ofthe rotor and stator discs respectively. As the rotor discs moverelative to the stator, there is a shearing action, as described above,between the edges of the abrupt walls 167' and 173'. This shearingaction tends to force the sheared material toward the bottom of thegrooves and laterally along the inclined edges 167" and 173", as well asoutwardly toward the outer ends of the grooves along the arcuateinclined bottoms thereof. When sufificiently reduced in size, thesheared and milled corn passes through the spaces between the rotor andstator discs and more particularly through and over the circular grooves168 and 168 formed in the milling surfaces of the discs where it isfurther reduced in size and converted to a creamy fluid. The material isreceived in the discharge passage 149 in the mill housing 147, for flowthrough discharge openings 181, 182, 183, 184 and 185 in the plates 143,141, 131, 128 and 125 respectively.

The degree of fineness of the grind produced in the first milling headand the pressure required to force the corn through the mill may bedetermined by adjusting the threaded cap 179 on the boss 178 of theouter cover plate 151. Preferably, the boss is calibrated, and thecylindrical body of the cap carries a pointer so that the adjustedposition may be read. It will be apparent that, by backing off the cap179, the space between the rotors and the stators will be increased,since the stators 156 and 157 and rotors 154 and 155 are free to movelongitudinally in the mill housing. Such adjustment reduces the pressurerequired to force the corn through the mill and the degree of finenessof the grind. Conversely, when the cap 179 is screwed up, the spacebetween the discs is decreased, the pressure requirements are increased,and the degree of fineness of the grind is increased.

The material is delivered from the discharge opening 106 in the backplate casting 125 to the other back plate casting 26 where it is againdelivered to the second positive displacement gear pump and forcedthrough the second milling head in substantially the same manner, exceptthat the fineness of the grind or the degree of reduction is greater inthe second milling head. The creamy liquid material is dischar ed fromthe machine through the opening 108, which is preferably connected to asuitable conduit for conveying the material to the next point in thecannery.

An important feature in the operation of this machine is the cooling ofthe material being treated, at least three times during its passagethrough the apparatus; first during its movement through the watercooled inlet passage 91 in the back plate casting 25; second, during itstransfer from the first milling head to the second, in the water cooledpassages 107 and 120 in back plate castings 25 and 26; and finallyduring its movement through the discharge passage 107 in back platecasting 26. This positive cooling of the material makes it possible toincrease the production of the mill very substantially withoutoverheating.

Another important feature of the operation of the apparatus is thetreatment of only very small quantities of material simultaneously atany one time, which is effected by the high speed passage of thematerial along a plurality of parallel paths between the millingsurfaces in a minimum of time. This high speed milling operation isaccomplished by the force feed of the material between the millingsurfaces and not by increasing the speed of rotation of the rotors,which is maintained at a low range, such as 600 r.p.m. Thus, thegeneration of heat and an undue rise in temperature in the materialbeing treated is avoided.

Although the invention has been described with considerableparticularity by reference to the modification shown in the accompanyingdrawings, it will thus be understood that it is not limited to thedetails of construction shown and described, but includes allmodifications coming within the scope of the appended claim and itsequivalents.

I claim:

A pump for delivering material to a mill or the like comprising a backplate casting having a pair of parallel shafts journaled therein andoverhung therefrom providing free end portions extending outwardly fromone end of said casting, a series of plates removably secured to saidone end of said casting in face to face relation, said series includinga pair of plates abutting each other secured adjacent said casting andhaving spaced shaft openings extending therethrough, a pump housingplate abutting the outer of said pair of plates and having fourcentrally intersecting openings extending therethrough, one pair of saidfour openings defining opposed circular pump element receiving chamberseach disposed in concentric relation to one of said shaft openings, theother pair of said four openings defining inlet and outlet chambers, thefree end portions of said shafts extending through said shaft openingsand said pump element receiving chambers, packing glands between saidpair of plates in surrounding engagement with said shafts, intermeshingpositive displacement gear pump elements fixed to said shafts withinsaid pump element receiving chambers, said casting and said pair ofplates having aligned material inlet openings therein communicating withsaid inlet chamber, said series of plates also including a front plateabutting the outer face of said housing plate closing the adjacent endof said inlet chamber, the adjacent faces of said front plate and theouter plate of said pair being in closely fitting relation to said gearpump elements, each of said gear pump elements having a plurality ofcircumferentially spaced gear teeth extending radially outwardlytherefrom, said teeth tapering slightly away from said adjacent facesfrom the roots of the teeth to the tips thereof to prevent scoring ofsaid adjacent faces in response to a slight canting movement of saidgear pump elements, said series of plates and gear pump elements beingremovable axially from the free end portions of said shafts, one of saidshafts being arranged to be driven, a driving gear fixed to said drivenshaft in spaced relation to the free end portion thereof, a driven gearon the other of said shafts, and means for securing said driven gear tosaid other shaft in meshing engagement with said driving gear in anydesired position of angular adjustment relative to said other shaft soas to control the positions of said gear pump elements relative to eachother when said driving and driven gears are in driving relation.

References Cited in the file of this patent UNITED STATES PATENTS383,789 Willingham May 29, 1888 388,190 Field Aug. 21, 1888 393,936Tecktonius Dec. 4, 1888 448,087 Simonson Mar. 10, 1891 488,947 ParkesDec. 27, 1892 643,782 Thame Feb. 20, 1900 748,385 Lester Dec. 29, 19031,182,967 Bowser May 16, 1916 1,659,771 Fox Feb. 21, 1928 1,712,157Morita May 7, 1929 1,927,395 Edwards Sept. 19, 1933 2,022,610 WendellNov. 26, 1935 2,477,004 Paget July 26, 1949 2,659,239 Nillson et a1 Nov.17, 1953 2,683,994 Whitfield July 20, 1954 FOREIGN PATENTS 343,344 GreatBritain Feb. 19, 1931 574,364 Great Britain Ian. 2, 1946 944,768 Germanylune 21, 1956

